ES6: The features I'm most excited about(justicen.com)

  somethingThatReturnsPromiseWithoutError()
    .then((res) => {
      return Promise.reject("some error");
    })
    .catch((err) => {
      console.log(err); // => some error
    });

  somethingThatReturnsPromise()
    .then((foo) => {
      return foo.bar;
      // Or if you like it more verbose
      return Promise.resolve(foo.bar);
      // Or pass bar to a function modifying bar that returns a promise
      return modifyBarReturnPromise(foo.bar);
    })
    .then((newBar) => {
      console.log(newBar);
    });

  somethingThatReturnsPromise()
    .then((first) => {
       doSomethingWithFirstAndReturnPromise(first)
         .then((second) => {
           console.log(first + second);
         });
    });

  .then(val => doSomeStuff())

  .then(val => {
    if (something) return successVal;
    else throw new Error("Failure");
  });

  let url  = getUrl(resource);
  let data = url.then(url => fetch(url))
  let updateData = d => _.assign(d, {field: 'newVal'}
  let update = join(url, data, (url, data) => sendUpdate(url, updateData(data))

    // Basic async function, resolves after n milliseconds
    function wait(n) {
      var promise = $.Deferred();
      setTimeout(promise.resolve, n);
      return promise;
    }

    wait(10)
      .then(function() {
        console.log('first');  // prints first after 10 milliseconds
        return wait(10);
      })
      .then(function() {
        console.log('second'); // prints second after 20 milliseconds
        return 'done';
      })

    var promise = $.Deferred();
    setTimeout(promise.reject, 100)

    promise.then(null, function () {
      return $.Deferred().resolve([]);
    }).done(function(arg) {
      console.log(arg); // Prints '[]'
    })